During the past year the relationships of birthweight to placental weight, maternal education, socioeconomic index, gestation at registration, year of birth, institution, body length at birth and head circumference at birth were analyzed. The particular relationships of birthweight to placental weight and to gestational age with respect to survivors and nkn-survivors were analyzed through the application kf a covariance prkgram. The results kf these studies are being compiled and cknstitute Phase I of the Birthweight-Gestational Age Study. A multivariant analysis is in progress to determine the relationship of birthweight as the dependent variable to a large number of antecedent (prenatal) independent variables. The component variable of a Birthweight Index has been established and will be explored to determine its predictive value for birthweight-gestational age outcomes. l l l